Dye diffusion transfer elements and process

ABSTRACT

Film units for use in color diffusion transfer systems exhibit reduced stain when provided with a layer comprising a polymeric anhydride having therein a low molecular weight ester of maleic or fumaric acid.

United States Patent 1191 Fix DYE DIFFUSION TRANSFER ELEMENTS AND PROCESS [75] Inventor: Delbert D. Fix, Rochester, NY.

[73] Assignee: Eastman Kodak Company,

Rochester, NY.

[22] Filed: Sept. 25, 1972 [21] Appl. No.2 292,008

[52] U.S. Cl 96/3, 96/29 D, 96/76 R, 96/77 [51] Int. Cl. G03c 7/00, G03c 5/54, G03c 1/48,

G030 H40 [58] Field of Search 96/3, 29 D, 77, 76 R [56] References Cited UNITED STATES PATENTS 3,227,551 1/1966 Barretal ..96/3

1111 3,820,990 June 28, 1974 l/l968 Land 96/3 7/1973 Dappen et a]. 96/3 Primary Examiner-R0nald H. Smith Assistant Examiner-Richard L. Schilling Attorney, Agent, or Firm-Dennis M. Deleo 57 ABSTRACT 19 Claims, N0 Drawings 1. Field of Invention This invention relates to the art of photography and more particularly, to color diffusion transfer film units, receiving elements and methods for obtaining stable diffusion transfer dye images of improved quality.

2. Description of the Prior Art Diffusion transfer receiving elements comprising a dye image-receiving layer with an underlying acid layer to reduce the alkalinity of the transfer image on the receiving element are well known in the art. For example, US. Pat. No. 3,362,819, issued Jan. 8, 1968, describes an image receiving element which contains a polymeric acid layer. Additional disclosures of similar uses of acidic layers are found in US. Pat. Nos. 2,584,030, 2,704,721, 2,983,606, Belgian Patent No. 603,747, dated'May 31, 1961 and others. The receiving elements of the type described in the above prior are are all reasonably effective when used in dye developer diffusion transfer processes as described, for example, in the above noted Pat. No. 2,983,606. However, the multilayer receiving elements of the prior art are not veryeffective in alleviating the stain which typically accompanies color diffusion transfer processes utilizing aromatic primary amino color developing agents.

US. Pat. No. 3,227,550 of Whitmore and Mader, issued Jan. 4, 1 966 and US. Pat. No. 3,227,552 of Whitmore, issued Jan. 4, 1966, describe photographic image transfer processes wherein an immobile coupler is reacted with oxidized aromatic primary amino color developing agent to form a mobile dye which is transferred by diffusion to a receiving layer to form a color image. During the development phase of the color development diffusion transfer process, the image dyes formed inthe respective blue, green and red-sensitive silver halide emulsion layers diffuse into an imagereceiving layer of the'receiving element where the dyes are mordanted to form the transferred image. At the same time, small amounts of development reaction products and unused color developer diffuse into the image-receiving layer. When the receiving element is separated from the photosensitive element, oxygen in the atmosphere causes rapid oxidation of the unused developer; self-coupling of the developer occurs, thereby producing a yellowish-brown stain, particularly in the highlight or minimum density areas. It would be desirable to reduce the stain.

US. Pat. No. 3,445,228, issued May 20, 1969, of Beavers et. al. discloses that a polymeric acid layer can be used in a filmunit which is developed using aromatic primary amino color developing agents. However, a white pigment containing interlayer is needed to conceal the stain which is formed in the acid layer. It would be desirable to further reduce or eliminate the resultant stain seen even in elements with these additional interlayers.

The described stain can be reduced through the appropriate use of a polymeric anhydride layer. In an effort to further reduce stain, the polymeric anhydride, e.g., a maleic anhydride polymer, can be hydrolyzed to various degrees. Although hydrolysis of the polymer affords some reduction in stain, it typically renders the polymer more brittle, especially after processing when the polymer is converted to its alkali metal salt. Thus, it would be desirable to reduce or eliminate stain without an accompanying increase in brittleness of the final imaged element.

SUMMARY OF THE INVENTION I have found that the stain typically accompanying color diffusion transfer processes utilizing nondiffusible color couplers and aromatic primary amino color developing agents can be significantly reduced through the use, in the image-receiving element portion of a film unit, of a polymeric anhydride layer having incorporated therein various high boiling organic acid ester liquids.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The objects of the present invention are achieved by a photographic film unit according to my invention,

which is adapted to be processed by passing the unit between a pair of juxtaposed pressure-applying members, such as would befoundin a camera designed for incamera processing, comprising:

a. a photosensitive element comprising a support having thereon at least one, and preferably three, photosensitive silver halide emulsion layers, each silver halide emulsion layer having associated therewith a dye image-providing material comprising a nondiffusible coupler capableof reacting with oxidized aromatic primary amino color developing agent to produce a diffusible dye;

b. a dye image-receiving layer;

c. a layer comprising a polymeric anhydride contain ing a low molecular weight ester of maleic or fumaric acid; and v d. means for discharging an alkaline processing composition within the film unit such as a rupturable container adapted to be positioned during processing of the film unit so that a compressive force applied to the container by the pressure-applying members will effect a discharge of the contents of the container within the film unit;

the above film unit containing an aromatic, primary amino color developing agent, preferably in the rupturable container. 1 y I The ester-containing. polymeric 1 anhydride layers used in accordance with. my invention stabilize the transferred dye images and at the same time, reduce stain particularly in the highlight areas. A variety of polymeric anhydrides can be used in the film units described herein. Typically, the anhydride used is at least partially hydrolyzed and generally, the anhydride contains from about 9 to about 40% free acid. The free acid content is determined by a non-aqueous titration procedure on the polymer or polymer blend prior to coating. The percent of free acid present is represented by times the ratio of the amount of acid present to the total amount of acid plus anhydride moieties present. A preferred range of said content is from about 10 to about 30%.

The anhydride layer can be a mixture of polymers such as a substantially unhydrolyzed anhydride with a suitable amount of a partially hydrolyzed anhydride so as to provide a free acid content within the described range. Maleic anhydride containing; polymers represent a preferred class of materials especially alkyl vinyl ether copolymers with maleic anhydride wherein the alkyl moiety contains from 1 to about 4 carbon atoms.

Other maleic anhydride copolymers include poly(styrene-co-maleic anhydride), poly(ethylene-co-maleic anhydride), poly(divinylether-co-maleic anhydride),

poly(hexene-co-maleic anhydride), poly(viny1 acetateco-maleic anhydride) and the like. The amount of the polymeric anhydride used in this invention can vary depending upon the particular configuration of use. Typically, the present anhydride layers are coated at a coverage of about 75 to about 250 mg/dm.

The low molecular weight esters used in accordance with this invention include lower alkyl esters having from 1 to about 6 carbon atoms in the alkyl moiety (e.g., methyl, ethyl, isopropyl, butyl, pentyl, cyclohexyl, etc) and lower alkenyl esters having 2 to about 6 carbon atoms in the alkenyl moiety. Representative esters thus include the dimethyl, methylethyl, diethyl, ethylpropyl, dialkyl, dibutyl, dipentyl, dicyclohexyl and like esters of fumaric or maleic acid. Preferred esters are those having a molecular weight in the range of about 170 to about 260. The amount of ester present in the anhydride layer can vary. Typically, the weight ratio of anhydride to ester is in the range of about 6 /2: 1 to about l/2:1. The ester-containing anhydride layer can also contain small amounts of suitable coating aids and/or other plasticizers.

My invention can be used not only in diffusion transfer systems wherein the image-receiving element is located on a separate support from the photosensitive e1- ement, but also in diffusion transfer systems wherein the image-receiving element is integral with the photosensitive element.

in one embodiment of my invention wherein the image-receiving element is separate from the photosensitive element, the novel dye image-receiving element comprises a support having thereon a layer of the described ester-containing polymeric anhydride and a dye image-receiving layer thereover. A timing layer, described hereinafter, can also be employed in the dye image-receiving element between the anhydride layer and the receiving layer to increase the stability of the transferred image. Although not required, a lightreflective layer comprising a white pigment in a binder can also be employed in the dye image-receiving element, if desired. The light-reflective layer can be located underneath the dye image-receiving layer or can be combined with a timing layer if one is employed.

The above-described dye image-receiving element of the film unit is adapted to be superposed on the photosensitive element after exposure thereof. The development and transfer operations can be effected by bathing either or both the exposed photosensitive element and the dye image-receiving element in a developing solution before rolling into contact with each other, or a viscous developing composition can be placed between the elements for spreading in a predetermined amount across and into contact with the exposed surface of the photosensitve elements. The viscous developing composition is desirably utilized in one or more pods attached to the reception sheet or photosensitive element that can be readily ruptured when development is desired as described, for example, in US. Pat. Nos. 2,559,643; 2,647,049; 2,661,293; 2,698,244; 2,698,798; and 2,774,668.

During the development phase of a color diffusion transfer process according to my invention, the dye image-providing material formed in the respective blue-, greenand red-sensitive silver halide emulsion layers diffuse out of the photosensitive element through the viscous developer composition and into the dye imagereceiving layer of the dye image-receiving element described above.

In another embodiment of my invention, the dye image-receiving layer is located integral with the photo sensitive element between the support and the lowermost photosensitive silver halide emulsion layer. Such integral receiver-negative photosensitive elements are described in Belgian Patent No. 757,960, granted April 23, 1971 of Barr, Bush and Thomasln such an embodiment, the support for the photosensitive element is transparent and is coated with the dye image-receiving layer, a substantially opaque, light-reflective layer, e. g., TiO and the various layers forming the color-forming units. After exposure of the photosensitive element, a rupturable container containing an alkaline processing composition and an opaque process sheet having the described polymeric anhydride layer coated thereon are brought into superposed position. Pressureapplying members in a camera rupture the container and spread processing composition over the photosensitive element as the film unit is withdrawn from the camera. The processing composition develops the exposed silver halide layers and dye images are formed as a function of development which diffuse to the imagereceiving layer to provide a positive, right-reading image which is viewed through the transparent support on the opaque reflecting layerbackground. For further details concerning. the format of this particular integral film unit, its preparation and use, reference is made to the above-mentioned Belgian Pat. No. 757,960, granted April 23, 1971.

Another embodiment of integral receiver-negative photosensitve systems in which my invention can be employed is described in Belgian Pat. No. 757,959, granted April 23, 1971, of Cole. In such an embodiment, the support for the color diffusion transfer system is transparent and is coated with the imagereceiving layer, a substantially opaque, light-reflective layer, e.g., TiO and then the various layers forming the color-forming units. A rupturable container containing an alkaline processing composition and an opacifier is positioned adjacent to the top layer and a transparent top sheet which is coated with the described polymeric anhydride layer. The film unit is placed in camera, exposed through the top transparent sheet and then passed between a pair of pressureapplying members in the camera as it is being removed therefrom. The pressure-applying members rupture the container and spread processing composition and opacifier over the negative portion of the film unit to render it light-insensitive. The processing composition develops the exposed silver halide layers and dye images are formed as a result of development which diffuse to the image-receiving layer to provide a positive,

right-reading image which is viewed through the transparent support on the opaque reflecting layer background. For further details concerning the format of this particular integral film unit, its preparation and use, reference is made to the above-mentioned Cole Belgian Pat. No. 757,959.

Still other useful integral formats in which my poly meric anhydride layer can be employed adjacent or near the dye image-receiving layer are described in US. Pat. Nos. 3,415,644; 3,415,645; 3,415,646; 3,647,437; and 3,635,707.

In the photographic film units according to my invention, there is associated with each silver halide emulsion layer in the photosensitive element a dye imageproviding material comprising a nondiffusible coupler which produces a diffusible dye on reaction with oxidized aromatic primary amino color developing agent in an alkaline processing composition.

The nondiffusible couplers employed in this invention include those having the formulas:

DYE LINK (COUP BALL) and BALL LINK (COUP SOL) wherein:

l. DYE is a dye precursor, e.g., a leuco dye, a shifted dye which shifts hypsochromically or bathochromically when subjected to a different environment such as a change in pH, reaction with a material to form a complex, etc; or a dye radical exhibiting selective absorption in the visible spectrum (includingmetal complexed dyes), the dye precursor or dye radical containing an acidic solubilizing radical;

2. LINK is a connecting radical which will split when the coupler is contacted with an oxidized aromatic primary amine such as an azo radical, a mercuri radical, an oxy radical, an alkylidene radical, a thio radical, a dithio radical, an azoxy radical, an aminoalkyl radical, a sulfonyloxy radical, an acyloxy radical or an imido radical;

3. COUP is a coupler radical such as a 5-pyrazolone coupler radical, a pyrazolotriazole coupler radical, a phenolic coupler radical or an open-chain ketomethylene coupler radical, COUP being substituted in the coupling position with LINK:

4. BALL is a photographically inert organic ballasting radical of such molecular size and configuration as to render such coupler nondiffusible during development in the alkaline processing composition;

5 SOL is a hydrogen atom or an acidic solubilizing group when the color developing agent contains an acidic solubilizing'group, and SOL is an acidic solubilizing group when the color developing agent is free of an acidic solubilizing group; and

6. n is an integer of lto 2.

For further details concerning the above-described couplers, their preparation and use, reference is made to US Pat. No. 3,227,550 of Whitmore et. al., issued Jan. 4, 1966; US. Pat. No. 3,227,552 of Whitmore, issued .Ian. 4, 1966; and British Pat. No. 904,364, page 19, lines l-4l.

The film assembly of my invention can be used to produce positive images in single or multicolors. In a three-color system, each silver halide emulsion layer of the film assembly of my invention will have associated therewith a dye image-providing material possessing a spectral absorption within the region of the visible spectrum to which said associated silver halide emulsion is sensitive, i.e., the blue-sensitive silver halide emulsion layer will have a yellow dye image-providing material associated therewith, the green-sensitive silver halide emulsion layer will have a magenta dye imageproviding material associated therewith, and the redsensitive silver halide emulsion layer will have a cyan dye image-providing material associated therewith.

The dye image-providing material associated with each silver halide emulsion layer can be contained either in the silver halide emulsion layer itself or in a layer contiguous to the silver halide emulsion layer.

Spectral sensitizing dyes can be used conveniently to conver additional sensitivity to the light sensitive silver halide emulsion of the multilayer photographic elements of the invention. Dyes useful for. this purpose are well known to those skilled in the art and are described in Product Licensing Index, Vol. 92, December, 197.1, publication 9232, pages 108-109, paragrph XV(A-D) Spectral Sensitization. In addition, the present emulsions can be chemically sensitized. as described on page 107, paragraph III, Chemical Sensitization of Product Licensing Index (supra).

The various silver halide smulsion layers of a color film assembly of the invention can be disposed in the usual order, i.e., the blue-sensitive silver halide emulsion layer first with respect to the exposure side, followed by the green-sensitive and red-sensitive silver halide emulsion layers. If desired, a yellow dye layer or a CareyLea silverlayercan be present between the blue-sensitive and green-sensitive silver halide emulsion layer for absorbing or filtering blue radiation that may be transmitted through the blue-sensitive layer. If desired, the selectively sensitized silver halide emulsion layers can be disposed in a different order, e.g., the blue-sensitive layer firstwith respect to the exposure side, followed by the red-sensitive and green-sensitive layers.

The silver halide are also well known in the art and are described on page 107, paragraph I, E'mulsion Types, Product Licensing Index (supra). The silver halide emulsions used in the practice of this invention can be protected against the reproduction of fog and can be stabilized against loss of sensitivity during keeping by employing the materials described onpage 107, paragraph V, Antifoggants and Stabilizers of the above article.

If the silver halide emulsion employed with the nondiffusible couplers described above is a direct positive silver halide emulsion, such as an internal image emulsion or a solarizing emulsion, which is developable in unexposed areas, a positiveimage can be obtained on the dye image-receiving layer. In this embodient, the nondiffusible coupler can be located in the silver halide emulsion itself. After exposure of the film unit, the alkaline processing composition permeates the various layers to initiate development of the exposed photosensitive silver halide emulsion layers. The aromatic primary amino color developing agent present in the film unit develops each of the silver halide emulsion layers in the'unexposed areas (since the silver halide emulsions are direct positive ones), thus causing the developing agent to become oxidized imagewise corresponding to the unexposed areas of the direct positive silver halide emulsion layers. The oxidized developing agent then reacts with the nondiffusible coupler present in each silver halide emulsion layer to form imagewise distributions, respectively, of diffusible cyan, magenta and yellow dye as a function of the imagewise exposure of each of the silver halide emulsion layers. At least a portion of the imagewise distributions of diffisuble cyan, magenta and yellow dye diffuse to the image-receiving layer to provide a positive dye image.

Internal image silver halide emulsions useful in the above-described embodiment are direct positive emulemulsions useful in this invention sions that form latent images predominantly inside the silver halide grains, as distinguished from silver halide grains that form latent images predominantly on the surface thereof. Such internal image emulsions were described by Davey et. al. in U.S. Pat. No. 2,592,250, issued Apr. 8, 1952, and elsewhere in the literature. These emulsions can also contain fogging or nucleating agents such as those described in U.S. Pat. Nos. 2,588,982; 2,563,785; 3,227,552; etc.

As previously mentioned, the aromatic primary amino color developing agent employed in the abovedescribed embodiment is preferably present in the alkaline processing composition in the rupturable pod. The color developing agent can also be incorporated into the negative portion of the film unit as a separate layer, e.g., by employing a Schiff base derivative of an aromatic primary amino color developing agent such as that formed by reacting o-sulfobenzaldehyde and N,N- diethyl-3-methyl-4-aminoaniline. Such incorporated developing agent will be activated by the alkaline processing composition. While the incorporated developing agent can be positioned in any layer of the photosensitive element from which'it can be readily made available for development upon activation with alkaline processing composition, it is generaly either incorporated in the light sensitive silver halide emulsion layers or in the layers contiguous thereto. As mentioned above, aromatic primary amino color developing agents employed in certain embodiments of this invention are preferably p-phenylenediamine developing agents. These developing agents are well known to those skilled in the art and include the following compounds and salts thereof:

4-amino-N,N-diethyl-3-methyl aniline,

N,N-diethyl-p-phenylenediamine,

N-ethyl-B-methane-sulfonamido-ethyl-3-methyl-4- amino aniline, 4-amino-N-ethyl-3-methyl-N-(B-sulfoethyl)aniline, 4-amino-N-ethyl-3-methoxy-N-(B-sulfoethyl)aniline,

' 83, polymeric materials such as polyvinylamides as disclosed in U.S. Pat. 3,421,892, or any ofthose disclosed in U.S. Pat. Nos. 2,992,104; 3,043,692; 3,044,873; 3,061,428; 3,069,263; 3,069,264; 3,121,011 and 3,427,158.

Generally speaking, except where noted otherwise, the silver halide emulsion layers in the invention comprise photosensitive silver halide dispersed in gelatin and are about 0.6 to 6 microns in thickness; the dye image-providing materials are dispersed in an aqueous a1- kaline solution-permeable polymeric binder, such as gelatin, as a separate layer about 1 to 7 microns in thickness; and the alkaline solution-permeable polymeric interlayers, e.g., gelatin, are about 1 to 5 microns in thickness. Of course, these thicknesses are approximate only and can be modified according to the product desired. In addition to gelatin, other suitable hydrophilic materials which can be employed include both naturally-occurring substances such as proteins, e.g., gelatin derivatives, cellulose derivatives, polysaccharides such as dextran, gum arabic and the like; and synthetic polymeric substances such as water soluble polyvinyl compounds like poly(vinylpyrrolidone), acrylamide polymers and the like.

The photographic emulsion layers and other layers of a photographic element of this invention can also contain alone or in combination with hydrophilic, w'aterpermeable colloids, other synthetic polymeric compounds such as those described in Product Licensing Index (supra), page 108, paragraph VlllB, Vehicles.

Any material can be employed as the image-receiving layer in this invention as long as the desired function of mordanting or otherwise fixing the dye images will be obtained. The particular material chosen will, of course, depend upon the dye to be mordanted. 1f acid dyes are to be mordanted, the image-receiving layer can contain basic polymeric mordants such as polymers of amino guanidine derivatives of vinyl methyl ketone such as described in Minsk U.S. Pat. No. 2,882,156, issued Apr. 14, 1959, and basic polymeric mordants such as described in copending U.S. application Ser. No. 100,491 ofCohen et al., filed Dec. 21, 1970, now U.S. Pat. No. 3,709,690. Other mordants useful in the invention include poly-4-vinylpyridine, the 2-vinyl pyridine polymer metho-p-toluene sulfonate and similar compounds described in Sprague et a1 U.S. Pat. No. 2,484,430, issued Oct. 11, 1949, and cetyl trimethylammonium bromide, etc. Effective mordanting compositions are also described in Whitmore U.S. Pat. No. 3,271,148 and Bush U.S. Pat. No.'3,271,l47, both issued Sept. 6, 1966.

Furthermore, the image-receiving layer can be sufficient by itself to mordant the dye as in the case of use of an alkaline solution-permeable polymeric layer such as N-methoxymethyl polyhexylmethylene adipamide, partially hydrolyzed polyvinyl acetate, polyvinyl alcohol with or without plasticizers, cellulose acetate, gelatin and other materials of a similar nature. Generally, good results are obtained when the image-receiving layer, preferably alkaline solution-permeable, is transparent and about 0.25 to about 0.40 mil in thickness. This thickness, of course, can be modified depending upon the result desired. The image-receiving layer can also contain ultraviolet absorbing materials to protect the mordanted dye images from fading due to ultraviolet light, brightening agents such as the stilbenes, coumarins, triazines, oxazoles, dye stabilizers such as the chromanols, alkyl phenols, etc.

The ester-containing polymeric anhydride layer utilized in elements of the present invention serves a twofold function. This layer, which is associated with the dye image-receiving element of the invention in one of the preferred embodiments of the invention, acts as a pl-l-lowering material which typically increases the stability of the transferred image. Generally, this material will effect a reduction in the pH of the image layer from about 13 or 14 to at least 11 and preferably -8 within a short time after imbibition. Such a reduction of the pH of the film unit after development terminates further development and substantially reduces further dye transfer all of which stabilizes the dye image.

In addition to the pH-lowering function of the polymeric anhydride layer, the materials described herein also provide a significant reduction in undesirable stain when used in color diffusion transfer film units which are developed with aromatic primary amino color de veloping agents. In diffusion transfer processes involving the formation of a diffusible dye by reacting a photographic color coupler with oxidized aromatic primary amino color developing agent, the transfer of color dye images to dye image-receiving layers is accompanied by small amounts of development reaction products and unused color eveloping agent. The transfer of such materials with the dye image to the receiving layer is objectionable in that the transferred materials frequently result in stain, particularly in the highlight or minimum density (D areas. The presence of the described esters in the polymeric anhydride layers set forth herein results in a scavenging of such excess color developing agents, etc, with a corresponding significant reduction of stain. This, in turn, results in images having clean highlight areas with good color balance and density. Additionally, images formed on the film units of the present invention exhibit improved image stability under a wide range of atmospheric conditions. The ester-containing polymeric anhydride layer described can be present as a separate layer between the dye image-receiving layer and its support where the receiver is a separate element or between the dye imagereceiving layer and the lowermost silver halide emulsion layerin an integral receiver-negative element or as a transparent cover sheetin an especially preferred embodiment of an integral receiver-negative element.

An inert timing or spacer layer can be employed in the practice of my invention. Such a layer is typically located over the polymeric anhydride layer and times or controls the pH reduction as'a function of the rate at which alkali diffuses through the inert spacer layer. Examples of such timing layers include gelatin,

polyvinylalcohol or any of those disclosed in U.S. Pat.

No. 3,455,686. The timing layer may also be effective in evening out the various reaction rates over a wide range of temperatures, e.g., premature pI-I reduction is prevented when imbibition is effected at temperatures above room temperature, for example, at 95 to 100F. The timing layer is usually about 0.1 to about 0.7 mil in thickness and may contain a light reflective material, such as titanium dioxide, if desired. Especially good results are obtained when the timing layer comprises a hydrolyzable polymer or a mixture of such polymers which are slowly hydrolyzed by the processing composition. Examples of such hydrolyzable polymers include polyvinyl acetate, polyamides, cellulose esters, etc.

The alkaline processing composition employed in this invention is the conventional aqueous solution of an alkaline material, e.g., sodium hydroxide, sodium carbonate or an amine such as diethylamine, preferably possessing a pHin excess of 12, and preferably containing a developing agentas described previously. The so lution also preferably contains a viscosity-increasing compound such as a high-molecular-weight polymer,

e.g., a water-soluble ether inert toakaline solutions such as hydroxyethyl cellulose or alkali metal salts of carboxymethyl cellulose such as sodium carboxymethyl cellulose. A concentration of viscosity-increasing compound of about 1 to about 5% by weight of the processing composition is preferred which will impart thereto a viscosity of about 100 cps. to about 200,000 cps.

While the alkaline processing composition used in this invention can be employed in a rupturable container, as describedpreviously, other methods of applying processing composition could be employed, e.g., bathing the photosensitive element in a processing bath, interjecting processing composition with communicating members similar to hypodermic syringes which are attached either to a camera or camera cartridge, etc.

While the film units of my invention can be modified so as to be employed in roll form, they are preferably used in cartridges similar to those described in U.S. Pat. Nos. 3,080,805; 3,161,118 and 3,161,122; said patents also illustrating typical cameras for performing color diffusion transfer processes of certain embodiments of my invention. I

The supports for the photographic elements of this invention can be any material as long as it does not deleteriously effect the photographic properties of the film unit and is dimensionally stable. Typical flexible sheet materials include cellulose nitrate film, cellulose acetate film, poly(vinyl acetal) film, polystyrene film, poly- (ethylene terephthalate) film, polycarbonate film, poly-a-olefins such as polyethylene and polypropylene film, and related films or resinous materials as well as glass, paper, metal, etc. The support is usually about 2 to 6 mils in thickness.

While the invention has been described with reference to layers of silver halide emulsions and dye imageproviding materials, dotwise coating, such as would be obtained using a gravure printing technique, could also be employed. In this technique, small dots of blue, green and red-sensitive emulsions have associated therewith, respectively, dots of yellow, magenta and cyan color-providing substances. After development, the transferred dyes would tend to fuse together into'a continuous tone.

The photographic layers employed in the practice of this invention can contain development modifiers, hardenersand coating aids as described on pages 107-108, paragraph IV, Development Modifiers, paragraph VII Hardeners and paragraph XII Coating Aids of Product Licensing Index (supra). These layers can be applied by any of the various techniques described on page 109, paragraph XVIII Coating Procedures of the preceding article.

The various layers, including the photographic layers, employed in the practice of this invention can contain light absorbing materials and filter dyes such as those described in Sawdey U.S. Pat. No. 3,253,921, issued May 31 1966; Gaspar U.S. Pat. No. 2,274,782, issued Mar. 3, 1942; Silverstein et al. U.S. Pat. No. 2,527,583, issued Oct. 31, 1950; and VanCampen U.S. Pat. No. 2,956,879, issued Oct. 18, 1960.

The sensitizing dyes and other a-ddenda used in the practice of this invention can be added from water so lutions or suitable organic solvent solutions may be used. The compounds can be added during various procedures including those described in Collins et al. U.S. Pat. No. 2,912,343, issued Nov. 10, 1959; McCrossen et al. U.S. Pat. No. 3,342,605, issued Sept. 19, 1967; Audran U.S. Pat. No. 2,996,287, issued Aug. 15, 1961, and Johnson et a1. U.S. Pat. No. 3,425,835, issued Feb. 4, 1969.

The following examples are included for a further understanding of the invention. Example 1 Twenty dye image-receiving elements are prepared by coating in order the following layers on an opaque polyester support, coverages in mg/dm are given in parenthesis:

Layer 1. See below Layer 2. Mordant (32), TiO (108), ZnO (11), 1,4-

butanediol diglycidyl ether (5.4)

Layer 3. Mordant (5.4), Gelatin (32) Layer 4. Gum arabic (1.1) The mordant used is po1y[styrene-co-N-benzyl-N,N- dimethyl-N-( 3-maleimidopropyl)ammonium chloride]. Layer 1, the developer scavenging layer, is comprised of po1y(methoxyethylene-co-maleic anhydride) coated at 178 mg/dm and 88 mg/dm of the designated maleate or fumarate ester. A multicolor photographic element of the type described in Example 1 of Whitmore et a1. U.S. Pat. No. 3,227,550, issued Jan. 9, 1966, is prepared. The emulsions are direct positive, gelatino, silver bromoiodide emulsions containing cyan, magenta and yellow dye-forming couplers in the red, green and blue light-recording emulsions, respectively. Samples of the described photosensitive element are exposed to a multicolor test object. The following processing composition is spread from a pod between the exposed surface of the photosensitive elements and the superposed image-receiving elements by passing the resultant transfer sandwiches between a pair of juxtaposed pressure rollers:

Potassium hydroxide 40.0 g. 4-amino-N-ethyl-N-B-hydroxyethylaniline 40.0 g. piperidinohexose reductone 0.2 g. S-methylbenzimidazole 0.05 g. l-phenyl-2-tetrazoline-5-thione 0.01 g. hydroxyethyl cellulose 22.0 g. Water to l liter After 60 seconds at 24C, each dye-image receiving element is peeled apart from the negative. One-half of each resultant image is immediately placed 20 cm. away from a General Electric Sunlamp ultraviolet light source to simulate sunlight conditions. It is kept there for 5 minutes with a fan blowing the warmed air over the surface at about 24 km/hr. (660 cm/sec.). The minimum reflection densities of the two halves of the receivers are then measured to incident blue light in a reflection densitometer. The following table indicates minimum densities both before and after the simulated sunlight treatment. The high values of Blue D,,,,,," indicate the presence of high levels of yellow-brown stain. Table 1 shows the results of these measurements. Part A of the table shows the effect of the esters on an essentially unhydrolyzed polymeric anhydride of Layer 1 (containing about 2% freeacid) and Part B shows the corresponding effect when the polymeric anhydride used in Layer 1 has been partially hydrolyzed (about 20% free acid).

Table 1 Effects of Maleate and Fuinarate Esters A. With 2% B. With 20% Hydrolyzed Polymer Hydrolyzed Polymer Sun- Difi'er Sun- Differlight ence light ence Orig. Test (Sun- Orig. Test (Sun- Blue Blue light Blue Blue light mln mln mln mln Dimethyl 0.35 1.02 .67 .22 .45 .23 Diethyl 1.10 1.64 l .54 .24 .52 .28 Dipropyl .66 1.13 .47 .22 .33 .11 Dibutyl .76 1.20 .44 .22 .37 .15 Maleate Dimethyl 1.15 1.56 .41 .22 .51 .29 Diethyl .77 1.06 .29 .22 .39 .17 Dipropyl .24 .74 .50 .21 .28 .07 Diallyl .40 .78 .38 .21 .31 .10 Dibutyl .34 .78 .44 .20 -.35 .15 Dicyclo- .82 1.10 .28 .28 .72 .44

hexyl Example 2 Receiving elements as described in Example 1 are prepared with varying degrees of polymer hydrolysis and two concentrations of dibutyl maleate in Layer 1. In all cases, the polymeric anhydride is coated at 178 mg/dm The resultant elements are tested as in Example 1 with the results shown in Table 11 below.

, The results show a large reduction of yellow stain both on the original and on the sunlight tests at the high concentration of dibutyl maleate when the polymer has been subjected to either low or high degrees of hydrolysis. Even the low concentration of dibutyl maleate is sufiicient to effect significant strain reduction at the higher levels of polymer hydrolysis. Example 3 Receiving elements of essentially the same composition as Example 1 are prepared. The developer scavenger layer comprises the polymeric anhydride at 200 mgldm either hydrolyzed or essentially unhydrolyzed, and varying concentrations of dibutyl maleate. Table 111 shows the data concerning the stain produced on processing according to the procedure described in Example except that the following developer composition is used:

-Cont1nued Smethylbenzimidazole 0.05 g. l-phenyl-2-tetrazoline-5-thione 0.01 g. hydroxyethyl cellulose 26 g. piperidinohexose reductone 0.2 g. p-xylene-a,a-diol 5 g. p-aminophenol hydrochloride I g.

Table Ill Concen- Sun- Polymer tration light Differ- Hydrolysis Dibutyl Original Test ence Maleate Blue Blue (Sunfree acid (mg/dm Dmh. D stain) The data show increasing reduction in sunlight stain as the concentration of dibutyl maleate is increased in coatings containing either partially hydrolyzed or substantially unhydrolyzed polymeric anhydride.

The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

l claim:

1. In a photographic film unit; adapted to be processed by passing said unitbetween a pair of juxtaposed pressure-applying members comprising:

a. a photosensitive element comprising a support having thereon at least one photosensitive silver halide emulsion layer, each said silver halide emulsion layer having association therewith a nondiffusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible dye;

b. a dye image-receiving layer;

c. a layer comprised of a polymeric anhydride; and

d. means for discharging an alkaline processing composition within. said film unit;

said film unit containing an aromatic primary amino color developing agent; the improvement wherein said layer of polymeric anhydride contains a member selected from the group consisting of lower alkyl and al kenyl esters of maleic and fumaric acid.

2. The film unit of claim 1 wherein said dye imagereceiving layer is located in said photosensitive element between said support and the lowermost photosensitive silver halide emulsion layer and said layer of polymeric anhydride is located on a transparent sheet which is coextensive with and superposed over the layer outermost from the support of said photosensitive element.

3. The film unit of claim 1 wherein said dye imagereceiving layer and said layer of polymeric anhydride are on a support separate from and adapted to be superposed on said photosensitive element after exposure thereof.

4. The film unit of claim 3 wherein said discharging means comprises a rupturable container and is so positioned during processing of said film unit that a compressivev force applied to said container by said pressure-applying members will effect a discharge of the contents of the container between said dye imagereceiving layer and the layer most remote from the support of said photosensitive element.

5. The film unit as described in claim 1 wherein said anhydride is a maleic anhydride polymer.

6. The film unit as described in claim 1 wherein said anhydride is a copolymer of an alkylvinyl ether and up to 50 mole percent maleic anhydride.

7. The film unit as described in claim 1 wherein said ester is selected from alkyl esters, having 1 to about 6 carbon atoms in the alkyl moiety, and alkenyl esters. having 2 to about 6 carbon atoms in the alkenyl moiety, of fumaric or maleic acid;

8. The film unit as described in claim 1 wherein said ester is presentin a weight ratio of polymeric anhydride to ester of about 6 /2:l to about l /2:l.

9. The film unit as described in claim 1 wherein said ester has a molecular weight of about to about 260.

10. ln a photographic film unit, adapted to be processed by passing said unit between a pair of juxtaposed pressure-applying members comprising:

a. a photosensitive element comprising a support having thereon at least one photosensitive silver halide emulsion layer, each said silver halide emulsion layer having associated therewith a nondiffusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible dye;

b. adye image-receiving element comprising a sup port having thereon a dye mordant layer; and

c. a rupturable container containing an alkaline processing composition and which is adapted to be po- 'sitioned during processing of said'film unit so that a compressive force applied to said container by said pressure-applying members will effect a discharge of the contents of the container between said dye image-receiving layer and the layer most remote from the support of said photosensitive element; said film unit containing an aromatic primary amino color developing agent; the improvement wherein said dye image-receiving element contains between said support and said dye mordant layer a layer comprising a'copolymer of methylvinyl ether and maleic anhydride, said copolymer containing an alkyl or alkenyl ester of maleic or fumaric acid,

said ester having a molecular weight of about 170 to about 260.

11. In a photographic film unit which is adapted to be processed by passing said unit between a pair of juxtaposed pressure-applying members comprising:

I. a photosensitive element comprising a support having thereon the following layers in sequence:

a. a direct-positive, red-sensitive silver halide emulsion layer containing a nondiffusible coupler capable. of reacting with oxidize-d aromatic primary amino color developing agent to produce a diffusible cyan dye;

b. an alkaline solution-permeable interlayer containing a compound capable of scavenging oxidized aromatic primary amino color developing agent;

c. a direct-positive, green-sensitive silver halide emulsion layer containing a non-diffusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible magenta dye;

d. an alkaline solution-permeable interlayer containing a compound capable of scavenging oxidized aromatic primary amino color developing agent; and

e. a direct-positive, blue-sensitive silver halide emulsion layer containing a non-diffusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible yellow dye;

each said non-diffusible coupler having the formula:

DYE LINK coup BALL)" BALL LINK (COUP SOL) wherein:

l. DYE is a dye precursor or a dye radical exhibiting selective absorption in the visible spectrum and containing an'acidic solubilizing group;

2. LINK is a connecting radical which will split when the coupler is contacted with an oxidized aromatic primary amine;

3. COUP is a coupler radical selected from the group consisting of a S-pyrazolone coupler radical, a pyrazolotriazole coupler radical, a phenolic coupler radical and an open-chain ketomethylene coupler radical, said COUP being substituted in the coupling position with said LINK;

4. BALL is a photographically inert organic ballasting radical of such molecular size and configuration as to render said coupler non-diffusible during development in said alkaline'processing composition;

5. SOL is selected from the group consisting of a hydrogen atom and an acidic solubilizing group when said color developing agent contains an acidic solubilizing group, and SOL is an acidic solubilizing group when said color developing agent is free of an acidic solubilizing group; and

6. n is an integer of l to 2.

II. a receiving element comprising a support having thereon a dye image-receiving layer, said element being adapted to be superposed over said bluesensitive silver halide emulsion layer after exposure of said photosensitive element; and

III. a rupturable container containing an alkaline processing composition and which is adapted to be positioned during processing of said film unit so that a compressive force applied to said container by said pressure-applying members will effect a discharge of the contents of said container between said dye image-receiving layer and said bluesensitive silver halide emulsion layer of said photosensitive element;

said film unit containing an aromatic primary amino color developing agent; the improvement wherein said dye image-receiving element contains a layer between said support and said dye image-receiving layer comprising a polymeric anhydride containing about 9 to about 40% free acid and having therein a lower alkyl or lower alkenyl ester of maleic or fumaric' acid.

12. The film unit as described in claim 10 wherein said polymeric anhydride is a copolymer comprising units of maleic anhydride.

13. The film unit as described in claim 12 wherein said polymeric anhydride is a copolymer of maleic anhydride and methylvinyl ether and contains about 10 to about free acid.

14. The film unit as described in claim 11 wherein said ester is present in a weight ratio of polymeric anhydride to ester of about 6 /221 to about l /2:l.

15. The film unit as described in claim 11 wherein said ester has a molecular weight of about 170 to about 260.

16. In a process for forming diffusion transfer images by treating with an alkaline processing composition an imagewise exposed photosensitive element comprising a support having thereon at least one photosensitive silver halide emulsion layer, each said layer having associated therewith a non-diffusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible dye, said treatment effecting development of each exposed silver halide emulsion layer to form an imagewise distribution of diffusible dye image-providing material at least a portion of which diffuses to a dye image-receiving layer of a dye image-receiving element, the improvement wherein said receiving element contains a layer of a polymeric anhydride having about 9 to about 40% free acid, said layer having therein an alkyl ester or an alkenyl ester of maleic or fumaric acid, said ester having a molecular weight of about 170 to about 260.

17. The process as described in claim 16 wherein said polymeric anhydride is a copolymer comprised of units of an alkylvinyl ether and up to 50 mole percent of units of maleic anhydride and'said ester is selected from the group consisting of diethyl, dipropyl, dipropenyl and dibutyl esters of maleic and fumaric acid.

18. The process of claim 16 wherein said treatment with an alkaline processing composition is effected by a. superposing over the layer outermost from the support of said photosensitive element said dye imagereceiving layer and polymeric anhydride layer coated on a support;

b. positioning a rupturable container containing said alkaline processing composition between said exposed photosensitive element and said dye imagereceiving layer; and

c. applying a compressive force to said container to effect a discharge of the contents of the container between said outermost layer of said exposed photosensitive element and said dye image-receiving layer.

19. A receiving element for diffusion transfer images comprising a support having thereon a layer of a poly meric anhydride containing a member selected from the group consisting of lower alkyl and lower alkenyl esters of maleic and fumaric acid, and a dye imagereceiving layer. 

2. The film unit of claim 1 wherein said dye image-receiving layer is located in said photosensitive element between said support and the lowermost photosensitive silver halide emulsion layer and said layer of polymeric anhydride is located on a transparent sheet which is coextensive with and superposed over the layer outermost from the support of said photosensitive element.
 2. LINK is a connecting radical which will split when the coupler is contacted with an oxidized aromatic primary amine;
 3. COUP is a coupler radical selected from the group consisting of a 5-pyrazolone coupler radical, a pyrazolotriazole coupler radical, a phenolic coupler radical and an open-chain ketomethylene coupler radical, said COUP being substituted in the coupling position with said LINK;
 3. The film unit of claim 1 wherein said dye image-receiving layer and said layer of polymeric anhydride are on a support separate from and adapted to be superposed on said photosensitive element after exposure thereof.
 4. The film unit of claim 3 wherein said discharging means comprises a rupturable container and is so positioned during processing of said film unit that a compressive force applied to said container by said pressure-applying members will effect a discharge of the contents of the container between said dye image-receiving layer and the layer most remote from the support of said photosensitive element.
 4. BALL is a photographically inert organic ballasting radical of such molecular size and configuration as to render said coupler non-diffusible during development in said alkaline processing composition;
 5. The film unit as described in claim 1 wherein said anhydride is a maleic anhydride polymer.
 5. SOL is selected from the group consisting of a hydrogen atom and an acidic solubilizing group when said color developing agent contains an acidic solubilizing group, and SOL is an acidic solubilizing group when said color developing agent is free of an acidic solubilizing group; and
 6. n is an integer of 1 to
 2. II. a receiving element comprising a support having thereon a dye image-receiving layer, said element being adapted to be superposed over said blue-sensitive silver halide emulsion layer after exposure of said photosensitive element; and III. a rupturable container containing an alkaline processing composition and which is adapted to be positioned during processing of said film unit so that a compressive force applied to said container by said pressure-applying members will effect a discharge of the contents of said container between said dye image-receiving layer and said blue-sensitive silver halide emulsion layer of said photosensitive element; said film unit containing an aromatic primary amino color developing agent; the improvement wherein said dye image-receiving element contains a layer between said support and said dye image-receiving layer comprising a polymeric anhydride containing about 9 to about 40% free acid and having therein a lower alkyl or lower alkenyl ester of maleic or fumaric acid.
 6. The film unit as described in claim 1 wherein said anhydride is a copolymer of an alkylvinyl ether and up to 50 mole percent maleic anhydride.
 7. The film unit as described in claim 1 wherein said ester is selected from alkyl esters, having 1 to about 6 carbon atoms in the alkyl moiety, and alkenyl esters, having 2 to about 6 carbon atoms in the alkenyl moiety, of fumaric or maleic acid.
 8. The film unit as described in claim 1 wherein said ester is presentin a weight ratio of polymeric anhydride to ester of about 6 1/2 :1 to about 1 1/2 :1.
 9. The film unit as described in claim 1 wherein said ester has a molecular weight of about 170 to about
 260. 10. In a photographic film unit, adapted to be processed by passing said unit between a pair of juxtaposed pressure-applying members comprising: a. a photosensitive element comprising a support having thereon at least one photosensitive silver halide emulsion layer, each said silver halide emulsion layer having associated therewith a non-diffusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible dye; b. a dye image-receiving element comprising a support having thereon a dye mordant layer; and c. a rupturable container containing an alkaline processing composition and which is adapted to be positioned during processing of said film unit so that a compressive force applied to said container by said pressure-applying members will effect a discharge of the contents of the container between said dye image-receiving layer and the layer most remote from the support of said photosensitive element; said film unit containing an aromatic primary amino color developing agent; the improvement wherein said dye image-receiving element contains between said support and said dye mordant layer a layer comprising a copolymer of methylvinyl ether and maleic anhydride, said copolymer containing an alkyl or alkenyl ester of maleic or fumaric acid, said ester having a molecular weight of about 170 to about
 260. 11. In a photographic film unit which is adapted to be processed by passing said unit between a pair of juxtaposed pressure-applying members comprising: I. a photosensitive element comprising a support having thereon the following layers in sequence: a. a direct-positive, red-sensitive silver halide emulsion layer containing a nondiffusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible cyan dye; b. an alkaline solution-permeable interlayer containing a Compound capable of scavenging oxidized aromatic primary amino color developing agent; c. a direct-positive, green-sensitive silver halide emulsion layer containing a non-diffusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible magenta dye; d. an alkaline solution-permeable interlayer containing a compound capable of scavenging oxidized aromatic primary amino color developing agent; and e. a direct-positive, blue-sensitive silver halide emulsion layer containing a non-diffusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible yellow dye; each said non-diffusible coupler having the formula: DYE - LINK - (COUP - BALL)n or BALL - LINK - (COUP - SOL)n wherein:
 12. The film unit as described in claim 10 wherein said polymeric anhydride is a copolymer comprising units of maleic anhydride.
 13. The film unit as described in claim 12 wherein said polymeric anhydride is a copolymer of maleic anhydride and methylvinyl ether and contains about 10 to about 30% free acid.
 14. The film unit as described in claim 11 wherein said ester is present in a weight ratio of polymeric anhydride to ester of about 6 1/2 :1 to about 1 1/2 :1.
 15. The film unit as described in claim 11 wherein said ester has a molecular weight of about 170 to about
 260. 16. In a process for forming diffusion transfer images by treating with an alkaline processing composition an imagewise exposed photosensitive element comprising a support having thereon at least one photosensitive silver halide emulsion layer, each said layer having associated therewith a non-diffusible coupler capable of reacting with oxidized aromatic primary amino color developing agent to produce a diffusible dye, said treatment effecting development of each exposed silver halide emulsion layer to form an imagewise distribution of diffusible dye image-providing material at least a portion of which diffuses to a dye image-receiving layer of a dye image-receiving element, the improvement wherein said receiving element contains a layer of a polymeric anhydride having about 9 to about 40% free acid, said layer having therein an alkyl ester or an alkenyl ester of maleic or fumaric acid, said ester having a molecular weight of about 170 to about
 260. 17. The process as described in claim 16 wherein said polymeric anhydride is a copolymer comprised of units of an alkylvinyl ether and up to 50 mole percent of units of maleic anhydride and said ester is selected from the group consisting of diethyl, dipropyl, dipropenyl and dibutyl esters of maleic and fumaric acid.
 18. The process of claim 16 wherein said treatment with an alkaline processing composition is effected by a. superposing over the layer outermost from the support of said photosensitive element said dye image-receiving layer and polymeric anhydride layer coated on a support; b. positioning a rupturable container containing said alkaline processing composition between said exposed photosensitive element and said dye image-receiving layer; and c. applying a compressive force to said container to effect a discharge of the contents of the container between said outermost layer of said exposed photosensitive element and said dye image-receiving layer.
 19. A receiving element for diffusion transfer images comprising a support having thereon a layer of a polymeric anhydride containing a member selected from the group consisting of lower alkyl and lower alkenyl esters of maleic and fumaric acid, and a dye image-receiving layer. 